This invention relates to a method for securing an extremely thin metal structure possessing a grid-like array of minute, closely spaced, precisely dimensioned apertures to a support member or carrier and the resulting supported microsieve.
Such an apertured metal structure, hereinafter referred to as a "microsieve", is especially useful in sorting and sieving objects of only a few microns in size. One such microsieve, designated a "cell carrier", is described in Spanish Pat. No. 522,207, granted June 1, 1984, and in commonly assigned, copending U.S. patent application Ser. No. 550,233, filed Nov. 8, 1983, the disclosure of which is incorporated by reference herein, for classifying biological cells by size. The cell carrier is prepared employing a modified photofabrication technique of the type used in the manufacture of transmission electron microscope grids. The cell carrier is on the order of only a few microns in thickness and possesses a numerically dense pattern of minute apertures. Even with the exercise of great care, the very delicate nature of the cell carrier makes it difficult to manipulate, for example, to insert it in a holder of the type shown in aforesaid U.S. patent application Ser. No. 550,233, without causing it appreciable damage, frequently in the form of a structural deflection or deformation which renders it useless for its intended use.
Laser-welding is a known technique for selectively fusing adjacent surfaces of the same, e.g., thermoplastic, material. Reference may be had in this respect to the disclosures of U.S. Pat. Nos. 3,974,016; 4,029,535; 4,069,080; 4,224,096; and, 4,461,947.